When abnormal cells grow inside the lobules of the breast, but have not spread to nearby tissue or beyond, the condition is called lobular carcinoma in situ (LCIS). The term "in situ" means "in place". With LCIS, the abnormal cells are still "in place" inside the lobules. Although the term LCIS includes the word “carcinoma”, LCIS is not invasive breast cancer.
Lobular carcinoma in situ (LCIS) and breast cancer risk
Although the abnormal cells are not malignant (cancer), LCIS increases the risk of getting breast cancer in either breast. LCIS has been considered a risk factor for breast cancer, but not a precursor (a condition that can develop into) to breast cancer. However, more recent evidence shows some LCIS may also develop into invasive lobular carcinoma (invasive breast cancer that begins in the lobules) [79-81].
Learn about LCIS and the risk of invasive breast cancer.
Breast cancer screening for women with LCIS
Because LCIS increases the risk of breast cancer, there are special screening guidelines for women with LCIS. Women with LCIS should :
- Have a mammogram every year
- Have clinical breast exam every six to 12 months
- Talk to their health care providers about screening with MRI
This medical care helps ensure that if breast cancer does develop, it is caught early when it is most treatable.
Risk-lowering options for women with LCIS
Risk-lowering drugs (chemoprevention)
Women with LCIS may take tamoxifen or raloxifene to try to prevent invasive breast cancer . Tamoxifen and raloxifene only reduce the risk of estrogen receptor-positive breast cancers. Neither drug reduces the risk of estrogen receptor-negative cancers . Tamoxifen lowers the risk of breast cancer by about 50 percent and raloxifene lowers risk by about 38 percent . Although raloxifene is slightly less effective than tamoxifen in reducing breast cancer risk, it has fewer harmful health effects . This makes raloxifene a better choice for some women.
Raloxifene is only for use among postmenopausal women, while both pre- and postmenopausal women can use tamoxifen.
Learn more about tamoxifen and raloxifene.
Learn about emerging areas in risk-lowering drugs for women at higher risk of breast cancer.
Preventive surgery (prophylactic mastectomy)
A more drastic option for lowering breast cancer risk is to have a prophylactic bilateral mastectomy. This surgery involves removing both breasts to try to keep cancer from developing.
Because regular breast cancer screening and tamoxifen (or raloxifene) are effective in greatly reducing risk, most women with LCIS choose these options over prophylactic bilateral mastectomy.
Learn more about options for women at higher risk.